====== Fuse ======

A fuse is a device that stops the flow of current once a current threshold is reached.  In electronic devices these are usually used for overcurrent protection.  In microeletronic devices these are typically used for configuration.

Example polysilicon fuses (National Semiconductor DMPAL16R):

{{::fuse:nat_semi_dmpal16r_block_ns100x.jpg?300|}}

Both the left and the bottom fuses are blown (non-conducting) but the upper right fuse is still conducting.

https://www.researchgate.net/figure/a-Difference-between-before-and-after-program-of-a-TSMC-eFuse-structure-in-Qualcomm_fig5_334624423

====== Anti-fuse ======

These are non-conductive until sufficient current flows through.  See Wikipedia for details.

Seems like there's lots of kinds. Example pics:

http://klabs.org/richcontent/fpga_content/Antifuse_Data/b4/unprogrammed_m2m_antifuse_b4.jpg

http://klabs.org/richcontent/fpga_content/Antifuse_Data/b4/programmed_m2m_antifuse_b4.jpg

http://klabs.org/richcontent/fpga_content/pages/notes/antifuse_notes.htm